Robo-origami sets a cyberfrontier

Most people can fold a piece of paper by the time they're in kindergarten, but it's not child's play for a robot, which must use complex mathematical formulas to accomplish the task.

That's why officials at Carnegie Mellon University are excited about a graduate student who has developed a robot capable of doing origami -- the traditional Japanese art of folding paper to make figures or sculptures.

Matthew Mason, a professor of computer science and robotics, thought building such a robot would be so daunting that he didn't encourage Devin Balkcom's plans to do so in January last year. But today, Balkcom has a robot that can make paper airplanes and hats and is scheduled to earn his doctorate with the project in August.

"Origami is way out there -- it's like a space shot," Mason said.

Origami important research applications because although robots have been taught to manipulate rigid objects such as golf clubs, they struggle when the objects are flexible, like paper or the human tissues that surgical robots must navigate.

As a result, robot origami helps measure a robot's ability to manipulate flexible objects, much as playing chess has become a way of measuring a computer's intelligence and speed, Mason and Balkcom said.

"To make a swan would be 10 PhDs worth of work," Balkcom said.

So if a child can learn how to make a folded paper swan, why is it rocket science for a robot?

Balkcom's may look fairly simple -- a small robot arm attached to a table that's something like a sheet metal press -- but every manipulation of the paper, and even the physical properties of paper itself, must be converted into the only language a robot understands: mathematics.

For example, paper might appear to be two-dimensional because it is so thin. But it has thickness that must be expressed mathematically so that the robot can account for what happens when the paper is folded (answer: it gets thicker).

As a result, the robot must be programmed to "understand" that paper can only be folded so much -- about seven times is the limit -- and that paper stretches ever so slightly when it is folded.

And doesn't even take into account fingers. Robots don't have them, so they don't have the nerves that allow a human to feel the paper. They also don't have the stereoscopic vision that allows humans to watch themselves fold the paper.

As a result, Balkcom's robot does origami in a manner different from that of your typical eight-year-old.

It uses a suction cup to pick and move the paper, which is manipulated over a gutter, or rut, on the metal surface. The paper is then pushed down into the gutter using a straight-edge ruler attached to the robotic arm, and the gutter closes on the paper to crease it.